Dear @amrit.p.nayak ,
The particle are injected from the spherical surface created on the base of the injection radius set in the SPECSOUR card. The fluence is inward only. However, particle are not injected in the radial (normal) direction only. So that, what you see in your results are particle emitted at different angles and that cross the entire geometry.
To cross check, you can increase the inner blackhole sphere and you will see the fluence gradually decrease.
Cheers,
Angelo